KURIYAMA Kan-e1 MATSUMOTO Noriko1 KASE Syuji1
This paper describes one of our most recent developments, the CENTUM CS Fieldbus Device Management Tool software. This software runs on a personal computer in the instrument room. It accesses field devices via the FOUNDATION™ fieldbus, in order to display status information and messages and enable parameters to be displayed and set. Remote access to field devices from the instrument room can greatly simplify their maintenance.
|Figure 1 Hierarchical Structure of Plant Management|
The phenomenon of the current era, coined the information age, involves a global trend toward digital technology and open architecture. Field devices are no exception to this trend. The next-generation field communication system succeeding 420 mA analog instrumentation and smart instrumentation, such as BRAIN and HART, has finally arrived and begun practical application. The system being referred to is the FOUNDATION™ fieldbus (hereinafter simply referred to as the fieldbus) – a bidirectional digital communication system. The architecture of the CENTUM CS already supports fieldbus, thus we have developed the Device Management Tool that is compatible with the fieldbus standard. This paper introduces the functions of the Fieldbus Device Management Tool.
In Section 2 of this paper, we will discuss how to deal with field devices in the fieldbus age (i.e., a broad survey of expectations regarding the maintenance of field devices). In Section 3 and thereafter, we will discuss the functions of the newly developed tool.
|Figure 2 System Configuration|
In this section, we will
1. Information on Field Devices
The following items of information relating to field devices are available.
2. Role of the Device Management Tool
Field devices include analog devices, smart communication devices such as the BRAINand HART-based instruments, and field devices capable of FOUNDATION™ Fieldbus communication, which all coexist in the same plant.
The Device Management Tool is concerned with the latter of these. From the information items of fieldbus-enabled devices discussed in Subsection 1, the Device Management Tool is designed to deal with 'online information.'
|Figure 3 Function List|
There are also tools, such as the Maintenance Support System1, for handling maintenance and reference information. In addition, there is a realm of asset management that covers all plant equipment, from electric devices such as motors, to programmable logic controllers and general office equipment, regardless of whether or not they are field devices. Figure 1 shows the hierarchical structure of plant management.
3. Expectations for Device Management, Maintenance Support and Asset Management
The user demand for field device management is based on a desire to increase the overall efficiency of not only device monitoring and inspection but also maintenance support and asset management with the aim of reducing maintenance costs over the plant's life cycle. An outline of how each of these objectives is to be achieved is given below.
This section discusses the functional configuration of the CENTUM CS Fieldbus Device Management Tool.
1. Intended Application
The Device Management Tool is designed to run on a PC connected to the CENTUM CS Enet/Ethernet. Figure 2 shows the configuration of the CENTUM CS fieldbus system.
2. Overview of Functions
Figure 3 shows the various functions provided by the Device Management Tool.
3. Data Flow
Figure 4 Data Flow and Database Structure
Figure 4 shows the flow of data and the database structure. The parameter data of various function blocks within the various field devices are processed through the ACF11 module, ICS and ACG using the fieldbus communication function, and then displayed in the relevant parameter windows.
The status of a field device is shown by acquiring the field device status data from the FCS. Messages from field devices are sent through the ACF11 module and FCS to the ICS for storage in its historical message file. Using the ICS's DDE server function, the Device Management Tool retrieves historical messages for display purposes.
The system has the following communication databases.
1. Device List Registration
1.1 Items on the Device List
The following summarizes the items that are defined on the device list. Items specified as "non-omissible" are essential for communication. All of the other items are auxiliary information and defined as necessary or not by the user.
The items from the device tag name to the model name (shown above) do not need to be entered if they are read from the host file set in the engineering tool.
1.2 Registration of Devices on the Device List
Devices are registered in the registration window. The registration window consists of a 'complete device list' registration window, which presents a list of registered devices, and an 'individual device list' registration window where data on devices are input.
1.3 Updating of a Device List ( Reading of Device Information )
The field devices defined in the device list registration windows can be included in the coverage of various monitoring functions, such as parameter and status displays, by executing the menu bar command for updating the device lists. The detailed information (including block configuration and each parameter's index information) that is necessary to communicate with devices (or show parameters) can be read at the same time the device list is updated, allowing parameters to be shown as necessary. Another separate dialog box can be retrieved in order to read more detailed information on the devices. Information reading can be repeated as many times as necessary. The system is designed to minimize users' burden of selection and definition. Users simply have to read the information for each device in the form of master data. We believe this strategy will greatly help communication with multi-vendor field devices (i.e., those of other manufacturers).
|Figure 5 Status and Paramter Display Windows|
2. Listing of Devices
The Device Management Tool lists details on the devices handled by the tool. The details can be shown in two window formats: a complete device list display or an individual device display.
2.1 Device List Table Display
The device list tabledisplay window is an all-in-one display of the details on devices handled by the Device Management Tool. In this window, users can search through the list by specifying a key word so as to list all of the devices of a specific vendor or the devices relating to a specific unit.
2.2 Device List on Individual Display
The individual device display window shows the details of a particular device included in the device list.
3. Status Window
The status window lists the statuses of devices handled by the Device Management Tool (i.e., the field devices connected to the CENTUM CS system). This window can be viewed in two formats: a segment-by-segment listing of the representative device statuses for all segments or a device-by-device display of the device statuses for a selected segment.
4. Parameter Display and Setting
The 'parameter display and setting' window is used to show and set the parameters for each function block of a device. These parameters can be shown either in the group corresponding to the VIEW object (an object prescribed in the FOUNDATION™ Fieldbus specifications that globally deals with the parameters of function blocks), or separately by individual selection. Figure 5 presents an example of the status window and the parameter display and setting window.
5. Message Displays
Messages given by devices are retrieved from the historical message file in the ICS (or PICS) for display on the screen. Taking advantage of the ICS's round-the-clock operation, users can view every single message relating to field devices.
6. Common Functions
This function is used to register users who are authorized to log on to the Device Management Tool before they do so and to restrict the kinds of operation available on a user-by-user basis. The logon procedure may be omitted to make all kinds of operation possible.
6.2 Record of Operations
This function is designed to maintain a record of the operations used to set the parameters of a field device and keep a record of the log-on and log-off occurrences.
This function prints the contents of each window in a report form.
This paper introduced the Device Management Tool that we developed as a means of engineering the CENTUM CS system in order to support the fieldbus standard. As discussed, there are a wide variety of devices in the field that must be supported in the future. These include not only fieldbus-enabled communication devices but smart communication devices as well. This tool is designed to cover those functions that are available online for the maintenance of field devices, but also acts as a framework for higher-order applications, such as maintenance support and asset management. In the future, we plan to develop other tools, such as maintenance support systems, that offer wide-ranging maintenance solutions based on the ETS concept.
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